Exynos542x: Add workaround for exynos iROM errata

iROM logic provides undesired jump address for CPU2.
This patch adds a programmable susbstitute for a part of
iROM logic which wakes up cores and provides jump addresses.
This patch creates a logic to make all secondary cores jump
to a particular address which evades the possibility of CPU2
jumping to wrong address and create undesired results.

Logic of the workaround:

Step-1: iROM code checks value at address 0x2020028.
Step-2: If value is 0xc9cfcfcf, it jumps to the address (0x202000+CPUid*4),
	else, it continues executing normally.
Step-3: Primary core puts secondary cores in WFE and store 0xc9cfcfcf in
	0x2020028 and jump address (pointer to function low_power_start)
	in (0x202000+CPUid*4).
Step-4: When secondary cores recieve event signal they jump to this address
	and continue execution.

Signed-off-by: Kimoon Kim <kimoon.kim@samsung.com>
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>